Habitat inputs for Reorienting to Recovery theoretical maximum habitat model run was scaled existing habitat to area curves using the 2018/2019 BiOp flows.
Fall Run Habitat
Spring Run Habitat
Winter Run Habitat
Non Run Specific Habitat
For each river reach in the SIT DSM, the theoretical maximum habitat was calculated for above and below dams and for unregulated rivers. See methodology for overview of theoretical maximum habitat modeling approach.
Theoretical maximum habitat was not calculated at specific flows and therefore to combine this new habitat with existing, the existing habitat to area curves were scaled using the following approach.
1) Calculate flow point of reference
For in-channel habitat we use the median flow over the entire modeled period 1980 - 2000. Flow inputs come from CalSim II benchmark from the 2019 Itp and 2020 BiOp. For floodplain habitat, we use a 2 year flow value, which represents a flow that is exceeded in 50% of the years between 1980 and 2000. This is done by take the yearly rolling maximum of monthly CalSim flows and applying a cumulative distribution function on the ranked values to find the proportion of all values less than or equal to the ranked order. An interpolation function is then developed to to find the 2 year flow value.
2) Calculate the proportion increase of habitat at flow point of reference
The proportion increase between baseline and theoretical maximum
habitat was calculated using the following equation. The
existing_acres were calculated using the median (for
in-channel) and 2-year flows (for floodplain).
proportion_increase = (max_hab_acres - existing_acres) / existing_acres + 1
3) Scale existing habitat by proportion increase
The existing acres are then scaled for each watershed
(ws) by the calculated
proportion_increase.
new_hab_acres <- DSMhabitat::fr_fp$biop_itp_2018_2019[ws , , ] * proportion_increase
4) Save new data objects for Theoretical Maximum Habitat
The new data objects are saved in the package as:
Fall Run
DSMhabitat::fr_spawn$r_to_r_tmh
DSMhabitat::fr_juv$r_to_r_tmh
DSMhabitat::fr_fry$r_to_r_tmh
DSMhabitat::fr_fp$r_to_r_tmh
Spring Run
DSMhabitat::sr_spawn$r_to_r_tmh
DSMhabitat::sr_juv$r_to_r_tmh
DSMhabitat::sr_fry$r_to_r_tmh
DSMhabitat::sr_fp$r_to_r_tmh
Winter Run
DSMhabitat::wr_spawn$r_to_r_tmh
DSMhabitat::wr_juv$r_to_r_tmh
DSMhabitat::wr_fry$r_to_r_tmh
DSMhabitat::wr_fp$r_to_r_tmh
Non Run Specific Habitat
DSMhabitat::delta_habitat$r_to_r_tmh See Calculating
Theoretical Maximum Habitat for details on Delta methodology for
theoretical maximum habitat